Devices for automatically feeding spare cartridge into the firing chamber of shotguns

ABSTRACT

A device for automatically feeding spare cartridges in the magazine tube into the firing chamber of a shotgun of the type comprising a piston mechanism for successively feeding the spare cartridge. The mechanism comprises a cup shaped piston receiver, a cup shaped piston slidable along the outer surface of the piston receiver, a shaft extending in the axial direction of the piston and the piston receiver for guiding the piston, the piston and piston receiver cooperating to define a gas chamber, a conduit for supplying the gas generated at the time of firing into the gas chamber, and means for discharging the gas from the gas chamber when the piston is moved to one of the extreme positions by the gas admitted into the gas chamber.

Unite States [191 [111 3,779,131

Kawamura Dec. 18, 1973 1 DEVICES FOR AUTOMATICALLY 2,052,368 8/1936 Sutter et al. 89/193 FEEDING SPARE CARTRIDGE INTO THE 877,657 1/1908 Mason 89/191 R FIRING CHAMBER OF SHOTGUNS Primary ExammerStephen C. Bentley [76] Inventor: k -l f" 9 1 AttorneyRaymond C. Stewart et al.

lshinazaka-machi, Hitachi-shi, Japan 57 ABSTRACT p 12, 1972 A device for automatically feeding spare cartridges in [21] Appl No: 243,284 the magazine tube into the firing chamber of a shotgun of the type comprising a piston mechanism for successively feeding the spare cartridge. The mecha- Foreign Application Priority Data nism comprises a cup shaped piston receiver, a cup A r. 21, 1971 Japan 46/25271 shaped piston slidable along the outer surface of the piston receiver, a shaft extending in the axial direction [52] [1.8. CI. 89/19] A, 89/193 of the piston and the piston receiver for guiding the [51] Int. Cl. F4ld 5/10 piston, the piston and piston receiver cooperating to [58] Field of Search 89/191 R, 191 A, define a gas chamber, a conduit for supplying the gas 89/192, 193 generated at the time of firing into the gas chamber,

and means for discharging the gas from the gas cham- [56] References Cited her When the piston is moved to one of the extreme UNITED STATES PATENTS positions by the gas admitted into the gas chamber.

3,420,140 H1969 Beretta 89/193 1 Claim, 3 Drawing Figures DEVICES FOR AUTOMATICALLY FEEDING SPARE CARTRIDGE INTO THE FIRING CHAMBER OF SI'IOTGUNS BACKGROUND OF THE INVENTION This invention relates to a firearm and more particularly to a shotgun provided with a gas operated device for automatically feeding spare cartridges into a firing chamber.

In firearms or shotguns, it has been well known to use a device in which a piston in a cylinder is moved by the propellant gas generated in the barrel to slide in one direction a sliding cylinder connected to the piston for unlocking a locking lever whereby a spare cartridge contained in a magazine is automatically fed into a firing chamber. The piston of this device is contained in the cylinder in such a manner that the piston is moved in one direction by the pressure of the gas entering the cylinder and returned in the opposite direction when the gas in the cylinder is exhausted.

In a device utilizing the above described pistoncylinder assembly, solids and contaminants admitted with the gas tend to deposit on the inner surface of the cylinder, whereby after a relatively small number of shoots, then deposited solids and contaminants prevent the smooth reciprocating motion of the piston and thus not only preventing normal operation but also damage a lever used to feed the spare cartridges.

SUMMARY OF THE INVENTION It is an object of this invention to provide an improved device for automatically feeding spare cartridges into the firing chamber of a firearm which can prevent deposition of the solids and contaminants contained in the propellant gas and even if such a deposition occurs, the normal operation of the piston is not with interfered.

Another object of this invention is to provide a gas actuated piston mechanism for successively feeding the spare cartridges into the firing chamber capable of protecting the shooter against the hot gas discharged from the feeding device.

According to this invention, a device for automatically feeding spare cartridges into the firing chamber of a shotgun comprises a magazine tube adapted to contain a plurality of spare cartridges and a piston mechanism operated by the gas generated at the time of firing for successively feeding the spare cartridges into the fire waiting chamber. The piston mechanism is constituted by a cup shaped piston receiver with its closed end secured to one end of the magazine tube, a cup shaped piston slidable along the outer surface of the piston receiver, a shaft extending in the axial direction of the piston and piston receiver for guiding the movement of the piston. The piston and piston receiver cooperate to define a gas chamber, a conduit for supply ing gas generated at the time of firing into the gas chamber, and means for discharging the gas from the gas chamber when the piston is moved to one of its extreme positions along the shaft by the gas admitted into the gas chamber.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a side view of a firearm embodying the invention;

FIG. 2 is an enlarged view, partly in section, of the device for automatically feeding spare cartridges utilized in the firearm shown in FIG. I; and

FIG. 3 is a view, partly in section, showing a modification of the device shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A shotgun 1 shown in FIG. 1 and embodying the novel device for automatically feeding spare cartridges comprises a barrel 2, a hollow housing 3 and a gunstock 4. Although not shown, like an ordinary shotgun, the housing 3 contains a firing room in which a spare cartridge is received and a mechanism for firing the spare cartridge. The cartridge in the firing room is shot by the firing mechanism actuated by a trigger 5. A hollow magazine tube 6 containing a feed device shown in FIG. 2 is secured on the lower side of barrel 2 to extend substantially in parallel therewith.

Coaxially mounted in the magazine tube 6 is a cylinder 7 of which opposite ends are opened and in which a plurality of spare cartridges 24 are disposed in the longitudinal direction thereof. The lefthand end of the cylinder 7 protrudes beyond the corresponding end of the magazine tube 6 and terminates near the inner end of the hollow housing 3, whereas the opposite end of cylinder 7 is closed by an enlarged head 9a of a hollow shaft 9 which slidably supports a piston to be described later. The righthand end of the shaft 9 is open while the lefthand end is closed by the enlarged head 9a. The righthand end of the shaft 9 extends through the end wall 10 of the magazine tube 6 in an airtight manner and is closed by a cap 11 threaded thereon. The cap 11 is provided with a central perforation 12 adapted to vent the inside of the hollow shaft 9. A cup shaped piston 13 and a piston receiver 14 of similar construction are contained in the righthand end of the magazine tube 6. Cylindrical portions of piston 13 and piston receiver l4 closely fit with each other to define a gas chamber 15. The end walls of piston 13 and piston receiver 14 are provided with central openings 16 and 17, respectively, through which shaft 9 extends in a gas tight manner. The piston receiver 14 is secured to the inside of the end wall 10 of the magazine tube 6, whereas the piston 13 is slidable along shaft 9. Consequently, as gas is admitted into gas chamber 15, the piston 13 alone is moved to the rear or left until it is stopped by head 9a of shaft 9 as shown in FIG. 2. The gas chamber 15 is communicated with the interior of the barrel 2 through a gas sonduit 18 extending through the end wall of the piston receiver 14 and the lower wall of barrel 2. To assure easy cleaning of the conduit 18 it is inclined to the rear as shown in FIG. 2. Near the inner end of hollow shaft 9 is provided a gas discharge passage 19 for communicating the interior of the gas chamber 15 with the central bore of shaft 9. This discharge passage 19 is opened only when the piston 13 is moved to the extreme lefthand position but closed by the end wall of piston 13 under other conditions.

A slidable tube 20 is closely mounted above the spare cartridge receiving cylinder 7, the slidable tube being constituted by a tube 21 provided with a pair of diametrically opposite axially extending arms 22 at one end thereof. The righthand end of tube 21 is connected to the end wall of piston 13 and the lefthand ends of the arms 22 project into the hollow housing 3.

A locking lever 23 of a well knwon construction is contained in the hollow housing 3. The locking lever 23 has an end 23a engageable with the end surface of a spare cartridge 24 contained in the lefthand end of cylinder 7. When the locking lever 23 is in engagement with the spare cartridge, the feeding of the spare cartridges into the firing chamber is precluded against the bias of a coil spring 25. When the slidable tube 20 is moved in the direction of arrow A, the locking lever 23 is disengaged from the cartridge thus feeding the innermost spare cartridge into the firing chamber. A coil spring 25 is contained in the fore or righthand end of the cylinder 7 and the righthand end of the spring 25 abuts against the enlarged head 9a of shaft 9. The lefthand end of the spring is provided with a cartridge seat 26 for urging the spare cartridges 24 contained in cylinder 7 towards the so that when the locking lever 23 is released, the innermost spare cartridge 24 will be fed automatically into the firing chamber.

The automatic feed device described above operates as follows.

A plurality of spare cartridges 24 are disposed in the spare cartridge receiving cylinder 7 and a single cartridge is loaded in the fire waiting chamber.

Under these conditions, slidable tube 20 and piston 13 are moved in the direction of arrow B, that is they assume the positions shown by dotted lines in FIG. 2 and the end 23a of the locking lever 23-is in engagement with the end surface of the innermost spare cartridge 24 thereby preventing the feeding thereof. Then, when the trigger is actuated to fire the cartridge in the firing chamber, the pressure gas generated in the barrel 2 will flow into gas chamber 15 via conduit 18 whereby piston 13 and slidable tube 20 are moved in the direction of arrow A. This movement of the slidable tube 20 causes its arms 22 to disengage locking lever 23 from the innermost spare cartridge 24. Consequently, by the action of spring 25, the innermost spare cartridge 24 will be automatically fed into the firing chamber through the lefthand opening of cylinder 7. At this time, discharge passage 19 is opened to exhaust the pressure gas in the gas chamber 15 through exhaust passage 19, the central bore in the shaft 9 and the perforation 12 through cap 11.

As the gas is discharged, the slidable tube 20 and piston 13 are returned to the original positions indicated by dotted lines by means of a spring, not shown, and the locking lever 23 is also returned to the original position th another spare cartridge which has been brought to the innermost position, thus preventing the feeding thereof.

In a firearm embodying the invention, above described operations are repeated each time a cartridge is fired whereby the spare cartridges 24 are contained in the cylinder 7 are successively fed and loaded in the firing chamber.

The novel device for automatically feeding spare cartridges described hereinabove is constructed such that the cup shaped piston and piston receiver cooperate to define a gas chamber, the piston slides along the outer surface of the piston receiver and as the piston is moved to one of its extreme positions, the gas in the gas chamber is exhausted. As a result, the solids and contaminants admitted into the gas chamber are efficiently discharged out of the gas chamber together with the gas. Further, since the solids and contaminants remaining in the gas chamber deposit mainly on the inner surface of the piston receiver and on the outer surface of shaft 9, said deposits do not interfere with the movement of the piston.

In the embodiment described above, since the gas in the gas chamber is exhausted in a direction opposite to the shooter through the hollow shaft mounted on the outer end of the magazine tube at a point remote from the shooter, there is no fear of damaging the same.

However, in order to simplify the construction the device may be modified as shown in FIG. 3 in which corresponding elements are designated by the same reference numerals as in FIG. 2. In this modified embodiment, a cup shaped piston 33 and a cup shaped piston receiver 34 are mounted on the righthand end of magazine tube 7 such that the piston is slidable with respect to the piston receiver. A shaft 29 is provided to extend through the center of the piston 33 and piston receiver 34 and to extend beyond the end wall of the magazine tube. The projected end of shaft 29 is closed by a cap 31. The inner end of the piston receiver 34 is notched as at 39 to form a discharge port for the gas contained in the gas chamber 15 so that when the piston 33 is displaced to the innermost position shown in FIG. 3, the gas in the gas chamber 15 is discharged to the outside through notch 39 and through the interior of the magazine tube 6.

Again the solids contained in the gas do not interfere with the movement of the piston.

What is claimed is:

l. A device for automatically feeding spare cartridges into a firing chamber of a shotgun comprising a magazine tube adapted to contain a plurality of spare cartridges and a piston mechanism operated by the gas generated at the time of firing for successively feeding said spare cartridges into the firing chamber, wherein said piston mechanism comprises a cup-shaped piston receiver with its closed end secured to one end of said magazine tube, a cup-shaped piston slidable along the outer surface of said piston receiver, a shaft extending in the axial direction of said piston and said piston receiver for guiding the movement of said piston, one end of said shaft protruding to the outside of said one end of said magazine tube, said piston and said piston receiver cooperating to define a gas chamber, a conduit for supplying the gas generated at the time of firing into said gas chamber, and gas discharge means for discharging the gas from said gas chamber when said piston is moved to one of its extreme positions along said shaft by the gas introduced into said gas chamber, said gas discharge means comprising a central bore through said shaft, a discharge opening provided through the peripheral wall of said shaft at such a point that said discharge opening is opened by said piston when the same is moved to said one extreme position, and a cap mounted on the protruded end of said shaft, said cap having a perforation for venting said central bore of said shaft. 

1. A device for automatically feeding spare cartridges into a firing chamber of a shotgun comprising a magazine tube adapted to contain a plurality of spare cartridges and a piston mechanism operated by the gas generated at the time of firing for successively feeding said spare cartridges into the firing chamber, wherein said piston mechanism comprises a cup-shaped piston receiver with its closed end secured to one end of said magazine tube, a cup-shaped piston slidable along the outer surface of said piston receiver, a shaft extending in the axial direction of said piston and said piston receiver for guiding the movement of said piston, one end of said shaft protruding to the outside of said one end of said magazine tube, said piston and said piston receiver cooperating to define a gas chamber, a conduit for supplying the gas generated at the time of firing into said gas chamber, and gas discharge means for discharging the gas from said gas chamber when said piston is moved to one of its extreme positions along said shaft by the gas introduced into said gas chamber, said gas discharge means comprising a central bore through said shaft, a discharge opening provided through the peripheral wall of said shaft at such a point that said discharge opening is opened by said piston when the same is moved to said one extreme position, and a cap mounted on the protruded end of said shaft, said cap having a perforation for venting said central bore of said shaft. 